Sutro Biopharma (STRO)
Sutro Biopharma on one page: short interest, daily short volume, fails to deliver, planned sales, large holders, 13F holders, earnings dates and insider trades. Listed on Nasdaq, classified by the SEC as biological products, (no diagnostic substances).
2.0M
Short interest
settlement 2026-10-15
6.3
Days to cover
-0.2 days vs prior
71.4%
Short share of volume
2026-11-02
8
Fails to deliver
settlement 2026-09-30
Thu 5 Nov
Next earnings
estimated date
$0
Insider flow, 90 days
0 buys, 0 sells
As of 2026-11-02.
Short interest
FINRA, twice a month. The newest 48 settlements in the table, 48 in the chart. JSONAs of 15 October 2026, short interest in STRO is 1,960,929 shares, down 115,223 shares over the last month. Over the last 48 readings it ranged from 404,777 shares (31 December 2025) to 7,562,777 shares (13 June 2025). At the reported average volume of 313K shares a day that is 6.3 days to cover.
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| Settlement | Shares short | Change | Avg daily volume | Days to cover |
|---|---|---|---|---|
| 2026-10-15 | 1,960,929 | +6.1% | 313,077 | 6.26 |
| 2026-09-30 | 1,847,453 | -11.0% | 285,322 | 6.47 |
| 2026-09-15 | 2,076,152 | +14.7% | 346,610 | 5.99 |
| 2026-08-31 | 1,809,482 | -2.5% | 212,030 | 8.53 |
| 2026-08-14 | 1,855,694 | +6.3% | 344,574 | 5.39 |
| 2026-07-31 | 1,744,843 | +5.6% | 274,760 | 6.35 |
| 2026-07-15 | 1,652,824 | +21.4% | 370,585 | 4.46 |
| 2026-06-30 | 1,361,955 | +47.7% | 590,796 | 2.31 |
| 2026-06-15 | 922,188 | +22.7% | 236,208 | 3.90 |
| 2026-05-29 | 751,365 | -37.0% | 434,201 | 1.73 |
| 2026-05-15 | 1,193,156 | +22.1% | 212,773 | 5.61 |
| 2026-04-30 | 977,108 | +30.5% | 250,098 | 3.91 |
| 2026-04-15 | 748,699 | +17.0% | 260,064 | 2.88 |
| 2026-03-31 | 639,714 | +20.1% | 228,901 | 2.79 |
| 2026-03-13 | 532,614 | +2.9% | 168,027 | 3.17 |
| 2026-02-27 | 517,388 | -19.8% | 100,424 | 5.15 |
| 2026-02-13 | 645,074 | +9.1% | 145,515 | 4.43 |
| 2026-01-30 | 591,301 | +11.9% | 117,536 | 5.03 |
| 2026-01-15 | 528,233 | +30.5% | 130,917 | 4.03 |
| 2025-12-31 | 404,777 | -27.8% | 108,736 | 3.72 |
| 2025-12-15 | 560,264 | -85.9% | 139,822 | 4.01 |
| 2025-11-28 | 3,977,435 | +12.9% | 626,998 | 6.34 |
| 2025-11-14 | 3,521,612 | +3.8% | 821,792 | 4.29 |
| 2025-10-31 | 3,393,235 | +35.4% | 2,310,500 | 1.47 |
| 2025-10-15 | 2,506,582 | +0.9% | 568,091 | 4.41 |
| 2025-09-30 | 2,484,864 | -1.3% | 423,111 | 5.87 |
| 2025-09-15 | 2,517,815 | -19.1% | 685,381 | 3.67 |
| 2025-08-29 | 3,111,092 | -11.9% | 398,257 | 7.81 |
| 2025-08-15 | 3,529,897 | +4.3% | 362,621 | 9.73 |
| 2025-07-31 | 3,383,900 | -7.5% | 581,703 | 5.82 |
| 2025-07-15 | 3,660,145 | -0.1% | 485,087 | 7.55 |
| 2025-06-30 | 3,663,856 | -51.5% | 1,867,684 | 1.96 |
| 2025-06-13 | 7,562,777 | +34.2% | 887,197 | 8.52 |
| 2025-05-30 | 5,634,191 | -17.8% | 766,661 | 7.35 |
| 2025-05-15 | 6,857,322 | +28.4% | 1,561,155 | 4.39 |
| 2025-04-30 | 5,339,311 | -1.5% | 3,197,987 | 1.67 |
| 2025-04-15 | 5,420,362 | +1.1% | 1,463,912 | 3.70 |
| 2025-03-31 | 5,363,800 | +15.7% | 1,940,139 | 2.76 |
| 2025-03-14 | 4,637,550 | +4.0% | 2,450,050 | 1.89 |
| 2025-02-28 | 4,460,835 | +1.1% | 656,153 | 6.80 |
| 2025-02-14 | 4,412,213 | +8.4% | 1,146,364 | 3.85 |
| 2025-01-31 | 4,070,738 | +5.7% | 844,316 | 4.82 |
| 2025-01-15 | 3,850,554 | +22.1% | 840,016 | 4.58 |
| 2024-12-31 | 3,154,647 | +28.4% | 1,191,212 | 2.65 |
| 2024-12-13 | 2,457,607 | +19.5% | 1,603,967 | 1.53 |
| 2024-11-29 | 2,056,651 | +15.0% | 1,048,195 | 1.96 |
| 2024-11-15 | 1,788,700 | -25.5% | 731,040 | 2.45 |
| 2024-10-31 | 2,400,803 | -16.1% | 379,416 | 6.33 |
Daily short volume
FINRA Reg SHO, the last 30 sessions. JSONAs of 2 November 2026, the short share of STRO volume is 71.4%, up 14.5 points over the last five sessions. Over the last 30 readings it ranged from 25.8% (28 October 2026) to 86.3% (29 September 2026). The latest reading is 12.0 points above the 30-session average of 59.4%, on 31K shares reported.
| Date | Short volume | Total volume | Short share | Exempt |
|---|---|---|---|---|
| 2026-11-02 | 22K | 31K | 71.4% | 0 |
| 2026-10-30 | 21K | 34K | 60.5% | 0 |
| 2026-10-29 | 35K | 100K | 35.0% | 0 |
| 2026-10-28 | 38K | 146K | 25.8% | 218 |
| 2026-10-27 | 47K | 143K | 32.8% | 1,861 |
| 2026-10-26 | 126K | 222K | 56.9% | 5,298 |
| 2026-10-23 | 88K | 135K | 65.1% | 176 |
| 2026-10-22 | 79K | 107K | 74.1% | 0 |
| 2026-10-21 | 141K | 189K | 74.6% | 1 |
| 2026-10-20 | 61K | 113K | 54.4% | 0 |
| 2026-10-19 | 47K | 83K | 56.3% | 0 |
| 2026-10-16 | 75K | 125K | 60.0% | 0 |
| 2026-10-15 | 104K | 160K | 65.3% | 0 |
| 2026-10-14 | 111K | 204K | 54.6% | 429 |
| 2026-10-13 | 78K | 137K | 56.7% | 1,347 |
| 2026-10-12 | 56K | 150K | 37.2% | 380 |
| 2026-10-09 | 68K | 86K | 78.2% | 0 |
| 2026-10-08 | 100K | 201K | 49.8% | 0 |
| 2026-10-07 | 46K | 71K | 64.9% | 0 |
| 2026-10-06 | 38K | 64K | 59.1% | 0 |
| 2026-10-05 | 33K | 68K | 48.8% | 0 |
| 2026-10-02 | 103K | 152K | 68.3% | 109 |
| 2026-10-01 | 38K | 61K | 62.5% | 0 |
| 2026-09-30 | 37K | 50K | 74.2% | 71 |
| 2026-09-29 | 62K | 72K | 86.3% | 0 |
| 2026-09-28 | 29K | 53K | 54.3% | 0 |
| 2026-09-25 | 70K | 105K | 66.5% | 0 |
| 2026-09-24 | 83K | 112K | 74.1% | 0 |
| 2026-09-23 | 80K | 129K | 62.0% | 0 |
| 2026-09-22 | 40K | 74K | 53.7% | 0 |
Fails to deliver
SEC, the last 30 settlement dates with a fail. JSONAs of 30 September 2026, the fails-to-deliver balance in STRO is 8 shares, down 102 shares over the last settlement date. Over the last 30 readings it ranged from 1 share (20 August 2026) to 7,778 shares (13 April 2026). The latest reading sits at the bottom of that range.
| Settlement | Shares failed | Price | Value |
|---|---|---|---|
| 2026-09-30 | 8 | $16.10 | $129 |
| 2026-09-25 | 110 | $15.71 | $2K |
| 2026-08-28 | 192 | $21.31 | $4K |
| 2026-08-26 | 4 | $21.44 | $86 |
| 2026-08-20 | 1 | $21.91 | $22 |
| 2026-08-12 | 19 | $25.04 | $476 |
| 2026-08-11 | 202 | $25.53 | $5K |
| 2026-07-23 | 1,069 | $23.40 | $25K |
| 2026-07-07 | 7 | $30.63 | $214 |
| 2026-06-29 | 30 | $30.52 | $916 |
| 2026-06-15 | 2,059 | $28.80 | $59K |
| 2026-05-26 | 487 | $25.57 | $12K |
| 2026-05-19 | 193 | $34.48 | $7K |
| 2026-05-11 | 4,673 | $40.24 | $188K |
| 2026-05-07 | 4,703 | $37.69 | $177K |
| 2026-05-04 | 964 | $35.59 | $34K |
| 2026-04-29 | 2,034 | $34.69 | $71K |
| 2026-04-20 | 39 | $31.55 | $1K |
| 2026-04-16 | 393 | $29.77 | $12K |
| 2026-04-15 | 404 | $28.78 | $12K |
| 2026-04-13 | 7,778 | $25.86 | $201K |
| 2026-03-06 | 379 | $22.50 | $9K |
| 2026-03-05 | 379 | $21.31 | $8K |
| 2026-03-02 | 1,313 | $20.47 | $27K |
| 2026-02-03 | 1,272 | $15.10 | $19K |
| 2026-01-14 | 136 | $10.63 | $1K |
| 2026-01-12 | 41 | $12.23 | $501 |
| 2026-01-08 | 209 | $11.75 | $2K |
| 2025-12-23 | 28 | $10.37 | $290 |
| 2025-12-17 | 2 | $9.81 | $20 |
Insider trades
SEC Form 4, newest first. JSONNo open-market insider trades were reported for STRO in the last 90 days. The most recent filings are listed below. Latest filing: Gerber Hans-Peter (CHIEF SCIENTIFIC OFFICER) on 2026-09-18.
| Date | Insider | Title | Type | Shares | Price | Value | Owned after |
|---|---|---|---|---|---|---|---|
| 2026-09-18 | Gerber Hans-Peter | CHIEF SCIENTIFIC OFFICER | Tax withholding | 1K | $15.34 | $21K | 12K |
| 2026-09-18 | Gerber Hans-Peter | CHIEF SCIENTIFIC OFFICER | Exercise or conversion | 4K | $0.00 | $0 | 14K |
| 2026-06-02 | Chow Gregory K. | CFO | Exercise or conversion | 3K | $0.00 | $0 | 5K |
| 2026-03-04 | Pauling David | Chief Admin. Ofcr. & GC | Tax withholding | 277 | $21.31 | $6K | 10K |
| 2026-03-04 | Pauling David | Chief Admin. Ofcr. & GC | Exercise or conversion | 675 | $0.00 | $0 | 10K |
| 2026-03-04 | Chung Jane | Chief Executive Officer | Tax withholding | 282 | $21.31 | $6K | 21K |
| 2026-03-04 | Chung Jane | Chief Executive Officer | Exercise or conversion | 788 | $0.00 | $0 | 22K |
| 2026-03-02 | Pauling David | Chief Admin. Ofcr. & GC | Tax withholding | 970 | $20.55 | $20K | 9K |
| 2026-03-02 | Pauling David | Chief Admin. Ofcr. & GC | Exercise or conversion | 2K | $0.00 | $0 | 10K |
| 2026-03-02 | Gerber Hans-Peter | CHIEF SCIENTIFIC OFFICER | Tax withholding | 1K | $20.55 | $24K | 10K |
| 2026-03-02 | Gerber Hans-Peter | CHIEF SCIENTIFIC OFFICER | Exercise or conversion | 3K | $0.00 | $0 | 11K |
| 2026-03-02 | Chung Jane | Chief Executive Officer | Tax withholding | 3K | $20.55 | $57K | 21K |
| 2026-03-02 | Chung Jane | Chief Executive Officer | Exercise or conversion | 8K | $0.00 | $0 | 24K |
| 2026-03-01 | Pauling David | Chief Admin. Ofcr. & GC | Tax withholding | 551 | $20.47 | $11K | 8K |
| 2026-03-01 | Pauling David | Chief Admin. Ofcr. & GC | Exercise or conversion | 842 | $0.00 | $0 | 9K |
| 2026-03-01 | Pauling David | Chief Admin. Ofcr. & GC | Exercise or conversion | 500 | $0.00 | $0 | 8K |
| 2026-03-01 | Gerber Hans-Peter | CHIEF SCIENTIFIC OFFICER | Tax withholding | 463 | $20.47 | $9K | 8K |
| 2026-03-01 | Gerber Hans-Peter | CHIEF SCIENTIFIC OFFICER | Exercise or conversion | 1K | $0.00 | $0 | 8K |
| 2026-03-01 | Chung Jane | Chief Executive Officer | Tax withholding | 1K | $20.47 | $26K | 16K |
| 2026-03-01 | Chung Jane | Chief Executive Officer | Exercise or conversion | 3K | $0.00 | $0 | 17K |
| 2026-03-01 | Chung Jane | Chief Executive Officer | Exercise or conversion | 688 | $0.00 | $0 | 15K |
| 2025-12-12 | Chung Jane | Chief Executive Officer | Tax withholding | 894 | $8.02 | $7K | 14K |
| 2025-12-12 | Chung Jane | Chief Executive Officer | Exercise or conversion | 3K | $0.00 | $0 | 15K |
| 2025-10-15 | Pauling David | Chief Admin. Ofcr. & GC | Buy | 13K | $0.80 | $10K | 72K |
| 2025-10-15 | MATSUI CONNIE | Director | Buy | 50K | $0.80 | $40K | 50K |
| 2025-10-15 | Gerber Hans-Peter | CHIEF SCIENTIFIC OFFICER | Buy | 17K | $0.80 | $14K | 72K |
| 2025-10-15 | Chung Jane | Chief Executive Officer | Buy | 13K | $0.80 | $10K | 123K |
| 2025-10-15 | Chow Gregory K. | CFO | Buy | 20K | $0.81 | $16K | 20K |
| 2025-09-18 | Gerber Hans-Peter | CHIEF SCIENTIFIC OFFICER | Tax withholding | 13K | $0.90 | $12K | 55K |
| 2025-09-18 | Gerber Hans-Peter | CHIEF SCIENTIFIC OFFICER | Exercise or conversion | 38K | $0.00 | $0 | 68K |
| 2025-08-09 | Chung Jane | Chief Executive Officer | Tax withholding | 7K | $0.80 | $5K | 110K |
| 2025-08-09 | Chung Jane | Chief Executive Officer | Exercise or conversion | 19K | $0.00 | $0 | 117K |
| 2025-07-08 | Leyman Barbara | Chief Business Officer | Tax withholding | 9K | $0.78 | $7K | 16K |
| 2025-07-08 | Leyman Barbara | Chief Business Officer | Exercise or conversion | 25K | $0.00 | $0 | 25K |
| 2025-05-15 | ALBINI EDWARD C | CFO AND SECRETARY | Exercise or conversion | 9K | $0.00 | $0 | 177K |
| 2025-05-15 | ALBINI EDWARD C | CFO AND SECRETARY | Exercise or conversion | 11K | $0.00 | $0 | 168K |
| 2025-05-15 | ALBINI EDWARD C | CFO AND SECRETARY | Tax withholding | 16K | $0.88 | $14K | 161K |
| 2025-05-15 | ALBINI EDWARD C | CFO AND SECRETARY | Exercise or conversion | 24K | $0.00 | $0 | 157K |
| 2025-05-01 | Borgman Anne Elizabeth | CHIEF MEDICAL OFFICER | Tax withholding | 25K | $1.07 | $26K | 97K |
| 2025-05-01 | Borgman Anne Elizabeth | CHIEF MEDICAL OFFICER | Exercise or conversion | 53K | $0.00 | $0 | 106K |
| 2025-05-01 | Borgman Anne Elizabeth | CHIEF MEDICAL OFFICER | Exercise or conversion | 16K | $0.00 | $0 | 122K |
| 2025-05-01 | Srinivasan Venkatesh | CHIEF TECH OP OFFICER | Tax withholding | 894 | $1.07 | $957 | 54K |
| 2025-05-01 | Srinivasan Venkatesh | CHIEF TECH OP OFFICER | Exercise or conversion | 3K | $0.00 | $0 | 55K |
| 2025-05-01 | FITZPATRICK LINDA A | CHIEF PEOPLE & COMM. OFFICER | Exercise or conversion | 13K | $0.00 | $0 | 127K |
| 2025-05-01 | FITZPATRICK LINDA A | CHIEF PEOPLE & COMM. OFFICER | Exercise or conversion | 6K | $0.00 | $0 | 133K |
| 2025-05-01 | FITZPATRICK LINDA A | CHIEF PEOPLE & COMM. OFFICER | Tax withholding | 14K | $1.07 | $14K | 120K |
| 2025-05-01 | FITZPATRICK LINDA A | CHIEF PEOPLE & COMM. OFFICER | Exercise or conversion | 10K | $0.00 | $0 | 114K |
| 2025-05-01 | FITZPATRICK LINDA A | CHIEF PEOPLE & COMM. OFFICER | Exercise or conversion | 9K | $0.00 | $0 | 105K |
| 2025-04-11 | Srinivasan Venkatesh | CHIEF TECH OP OFFICER | Tax withholding | 8K | $0.60 | $5K | 52K |
| 2025-04-11 | Srinivasan Venkatesh | CHIEF TECH OP OFFICER | Exercise or conversion | 21K | $0.00 | $0 | 60K |
| 2025-03-05 | ALBINI EDWARD C | CFO AND SECRETARY | Tax withholding | 4K | $1.36 | $5K | 132K |
| 2025-03-05 | ALBINI EDWARD C | CFO AND SECRETARY | Exercise or conversion | 9K | $0.00 | $0 | 136K |
| 2025-03-05 | FITZPATRICK LINDA A | CHIEF PEOPLE & COMM. OFFICER | Exercise or conversion | 9K | $0.00 | $0 | 99K |
| 2025-03-05 | FITZPATRICK LINDA A | CHIEF PEOPLE & COMM. OFFICER | Tax withholding | 4K | $1.36 | $5K | 95K |
| 2025-03-05 | NEWELL WILLIAM J | CEO | Tax withholding | 7K | $1.36 | $9K | 293K |
| 2025-03-05 | NEWELL WILLIAM J | CEO | Exercise or conversion | 19K | $0.00 | $0 | 299K |
| 2025-03-04 | Chung Jane | PRESIDENT AND COO | Tax withholding | 2K | $1.42 | $3K | 98K |
| 2025-03-04 | Chung Jane | PRESIDENT AND COO | Exercise or conversion | 8K | $0.00 | $0 | 101K |
| 2025-03-04 | NEWELL WILLIAM J | CEO | Tax withholding | 11K | $1.42 | $16K | 280K |
| 2025-03-04 | NEWELL WILLIAM J | CEO | Exercise or conversion | 31K | $0.00 | $0 | 292K |
| 2025-03-04 | FITZPATRICK LINDA A | CHIEF PEOPLE & COMM. OFFICER | Tax withholding | 4K | $1.42 | $5K | 90K |
| 2025-03-04 | FITZPATRICK LINDA A | CHIEF PEOPLE & COMM. OFFICER | Exercise or conversion | 9K | $0.00 | $0 | 94K |
| 2025-03-04 | ALBINI EDWARD C | CFO AND SECRETARY | Exercise or conversion | 9K | $0.00 | $0 | 131K |
| 2025-03-04 | ALBINI EDWARD C | CFO AND SECRETARY | Tax withholding | 4K | $1.42 | $5K | 127K |
| 2025-03-01 | Borgman Anne Elizabeth | CHIEF MEDICAL OFFICER | Tax withholding | 5K | $1.59 | $7K | 53K |
| 2025-03-01 | Borgman Anne Elizabeth | CHIEF MEDICAL OFFICER | Exercise or conversion | 11K | $0.00 | $0 | 58K |
| 2025-03-01 | Srinivasan Venkatesh | CHIEF TECH OP OFFICER | Tax withholding | 5K | $1.59 | $7K | 38K |
| 2025-03-01 | Srinivasan Venkatesh | CHIEF TECH OP OFFICER | Exercise or conversion | 5K | $0.00 | $0 | 37K |
| 2025-03-01 | Srinivasan Venkatesh | CHIEF TECH OP OFFICER | Exercise or conversion | 6K | $0.00 | $0 | 43K |
| 2025-03-01 | NEWELL WILLIAM J | CEO | Exercise or conversion | 24K | $0.00 | $0 | 244K |
| 2025-03-01 | NEWELL WILLIAM J | CEO | Tax withholding | 25K | $1.59 | $40K | 261K |
| 2025-03-01 | NEWELL WILLIAM J | CEO | Exercise or conversion | 42K | $0.00 | $0 | 286K |
| 2025-03-01 | Gerber Hans-Peter | CHIEF SCIENTIFIC OFFICER | Tax withholding | 5K | $1.59 | $7K | 31K |
| 2025-03-01 | Gerber Hans-Peter | CHIEF SCIENTIFIC OFFICER | Exercise or conversion | 11K | $0.00 | $0 | 35K |
| 2025-03-01 | FITZPATRICK LINDA A | CHIEF PEOPLE & COMM. OFFICER | Exercise or conversion | 13K | $0.00 | $0 | 93K |
| 2025-03-01 | FITZPATRICK LINDA A | CHIEF PEOPLE & COMM. OFFICER | Tax withholding | 8K | $1.59 | $13K | 85K |
| 2025-03-01 | FITZPATRICK LINDA A | CHIEF PEOPLE & COMM. OFFICER | Exercise or conversion | 7K | $0.00 | $0 | 80K |
| 2025-03-01 | Chung Jane | PRESIDENT AND COO | Exercise or conversion | 25K | $0.00 | $0 | 102K |
| 2025-03-01 | Chung Jane | PRESIDENT AND COO | Exercise or conversion | 7K | $0.00 | $0 | 77K |
| 2025-03-01 | Chung Jane | PRESIDENT AND COO | Tax withholding | 9K | $1.59 | $15K | 93K |
| 2025-03-01 | ALBINI EDWARD C | CFO AND SECRETARY | Exercise or conversion | 17K | $0.00 | $0 | 132K |
| 2025-03-01 | ALBINI EDWARD C | CFO AND SECRETARY | Tax withholding | 10K | $1.59 | $16K | 122K |
| 2025-03-01 | ALBINI EDWARD C | CFO AND SECRETARY | Exercise or conversion | 8K | $0.00 | $0 | 115K |
| 2025-02-28 | Borgman Anne Elizabeth | CHIEF MEDICAL OFFICER | Tax withholding | 15K | $1.59 | $24K | 46K |
| 2025-02-28 | Borgman Anne Elizabeth | CHIEF MEDICAL OFFICER | Exercise or conversion | 38K | $0.00 | $0 | 62K |
| 2024-12-01 | Chung Jane | PRESIDENT AND COO | Exercise or conversion | 25K | $0.00 | $0 | 79K |
| 2024-12-01 | Chung Jane | PRESIDENT AND COO | Tax withholding | 9K | $2.69 | $24K | 70K |
| 2024-09-18 | Gerber Hans-Peter | CHIEF SCIENTIFIC OFFICER | Tax withholding | 13K | $3.95 | $53K | 24K |
| 2024-09-18 | Gerber Hans-Peter | CHIEF SCIENTIFIC OFFICER | Exercise or conversion | 38K | $0.00 | $0 | 38K |
| 2024-08-09 | Chung Jane | PRESIDENT AND COO | Exercise or conversion | 19K | $0.00 | $0 | 61K |
| 2024-08-09 | Chung Jane | PRESIDENT AND COO | Tax withholding | 7K | $3.12 | $21K | 54K |
| 2024-05-01 | Srinivasan Venkatesh | CHIEF TECH OP OFFICER | Tax withholding | 892 | $3.74 | $3K | 32K |
| 2024-05-01 | Srinivasan Venkatesh | CHIEF TECH OP OFFICER | Exercise or conversion | 3K | $0.00 | $0 | 33K |
| 2024-04-11 | Srinivasan Venkatesh | CHIEF TECH OP OFFICER | Exercise or conversion | 21K | $0.00 | $0 | 38K |
| 2024-04-11 | Srinivasan Venkatesh | CHIEF TECH OP OFFICER | Tax withholding | 8K | $4.50 | $34K | 30K |
| 2024-03-05 | ALBINI EDWARD C | CFO AND SECRETARY | Exercise or conversion | 9K | $0.00 | $0 | 110K |
| 2024-03-05 | ALBINI EDWARD C | CFO AND SECRETARY | Tax withholding | 3K | $4.54 | $14K | 107K |
| 2024-03-05 | NEWELL WILLIAM J | CEO | Tax withholding | 7K | $4.54 | $30K | 220K |
| 2024-03-05 | NEWELL WILLIAM J | CEO | Exercise or conversion | 19K | $0.00 | $0 | 227K |
| 2024-03-05 | FITZPATRICK LINDA A | CHIEF PEOPLE & COMM. OFFICER | Tax withholding | 3K | $4.54 | $14K | 73K |
Form 4 filings are due within two business days of the trade. Insiders sell for many reasons that say nothing about the company; open-market buys are rarer.
Planned sales (Form 144)
Newest first. JSON1 Form 144 notice on file for STRO worth $131K at the prices reported; 0 in the last 90 days worth $0. Latest: BARBARA LEYMAN filed on 2026-01-20 to sell 8,929 shares ($131K) from 2026-01-20.
| Filed | Seller | Shares | Market value | Of outstanding | Sale from | Broker |
|---|---|---|---|---|---|---|
| 2026-01-20 | BARBARA LEYMANFormer Officer | 9K | $131K | 0.105% | 2026-01-20 | Morgan Stanley Smith Barney LLC Executive Financial Services |
Large holders (13D and 13G)
One row per reporting person with its latest filing, newest first. JSON15 holders report 5% or more of STRO in their latest filing, all on Schedule 13G (passive). The largest reported stake is Joseph Edelman at 7.9% of the class (1,304,846 shares), filed 2026-08-14 for an event on 2026-06-30.
| Filed | Form | Holder | Shares | Of class | Event |
|---|---|---|---|---|---|
| 2026-08-14 | 13G/Ano. 1 | Joseph Edelmanindividual | 1.3M | 7.9% | 2026-06-30 |
| 2026-08-14 | 13G/Ano. 1 | Perceptive Life Sciences Master Fund, Ltd.corporation | 1.3M | 7.9% | 2026-06-30 |
| 2026-08-14 | 13G/Ano. 1 | Perceptive Advisors LLCinvestment adviser | 1.3M | 7.9% | 2026-06-30 |
| 2026-08-14 | 13G/Ano. 1 | Point72 Asset Management, L.P.partnership | 238K | 1.4% | 2026-06-30 |
| 2026-08-14 | 13G/Ano. 1 | Point72 Capital Advisors, Inc.corporation | 238K | 1.4% | 2026-06-30 |
| 2026-08-14 | 13G/Ano. 1 | Steven A. Cohenindividual | 238K | 1.4% | 2026-06-30 |
| 2026-07-30 | 13G | BlackRock, Inc.parent holding company | 1.1M | 6.4% | 2026-06-30 |
| 2026-05-15 | 13G/Ano. 1 | Kynam Capital Management, LPinvestment adviser | 0 | 5.3% | 2026-03-31 |
| 2026-05-15 | 13G/Ano. 1 | Yue Tangindividual | 0 | 5.3% | 2026-03-31 |
| 2026-05-15 | 13G/Ano. 1 | Kynam Capital Management GP, LLCother entity | 0 | 5.3% | 2026-03-31 |
| 2026-05-15 | 13G | Srinivas Akkarajuindividual | 1.1M | 6.4% | 2026-02-11 |
| 2026-05-15 | 13G | Samsara Opportunity Fund, L.P.partnership | 644K | 3.9% | 2026-02-11 |
| 2026-05-15 | 13G | Samsara Opportunity Fund GP, LLCother entity | 644K | 3.9% | 2026-02-11 |
| 2026-05-15 | 13G | Samsara BioCapital GP, LLCother entity | 419K | 2.5% | 2026-02-11 |
| 2026-05-15 | 13G | Samsara BioCapital, L.P.partnership | 419K | 2.5% | 2026-02-11 |
| 2026-05-14 | 13G/Ano. 2 | Affinity Asset Advisors, LLCinvestment adviser, other entity | 1.1M | 6.5% | 2026-03-31 |
| 2026-05-14 | 13G/Ano. 2 | Michael Choindividual, parent holding company | 1.1M | 6.5% | 2026-03-31 |
| 2026-04-21 | 13G/Ano. 1 | Millennium Management LLCother entity | 210K | 1.3% | 2026-03-31 |
| 2026-04-21 | 13G/Ano. 1 | Millennium Group Management LLCother entity | 210K | 1.3% | 2026-03-31 |
| 2026-04-21 | 13G/Ano. 1 | Israel A. Englanderindividual | 210K | 1.3% | 2026-03-31 |
| 2026-02-18 | 13G | LAMPERT MARK Nindividual | 1.3M | 7.6% | 2026-02-10 |
| 2026-02-18 | 13G | BVF PARTNERS L P/ILinvestment adviser, partnership | 1.3M | 7.6% | 2026-02-10 |
| 2026-02-18 | 13G | BVF INC/ILcorporation | 1.3M | 7.6% | 2026-02-10 |
| 2026-02-18 | 13G | BVF GP HOLDINGS LLCother entity | 1.2M | 7.0% | 2026-02-10 |
| 2026-02-18 | 13G | BIOTECHNOLOGY VALUE FUND L Ppartnership | 669K | 4.1% | 2026-02-10 |
| 2026-02-18 | 13G | BVF I GP LLCother entity | 669K | 4.1% | 2026-02-10 |
| 2026-02-18 | 13G | BVF II GP LLCother entity | 489K | 3.0% | 2026-02-10 |
| 2026-02-18 | 13G | BIOTECHNOLOGY VALUE FUND II LPpartnership | 489K | 3.0% | 2026-02-10 |
| 2026-02-18 | 13G | Biotechnology Value Trading Fund OS LPpartnership | 75K | 0.5% | 2026-02-10 |
| 2026-02-18 | 13G | BVF Partners OS Ltd.corporation | 75K | 0.5% | 2026-02-10 |
| 2026-02-13 | 13G/Ano. 5 | SUVRETTA CAPITAL MANAGEMENT, LLCinvestment adviser, other entity | 0 | 0.0% | 2025-12-31 |
| 2026-02-13 | 13G/Ano. 5 | AVERILL MASTER FUND, LTD.corporation | 0 | 0.0% | 2025-12-31 |
| 2026-02-13 | 13G/Ano. 5 | AARON COWENparent holding company, individual | 0 | 0.0% | 2025-12-31 |
| 2025-10-23 | 13G | Affinity Healthcare Fund, LPpartnership | 6.6M | 7.8% | 2025-10-16 |
13F holders
Tracked managers holding STRO at their latest 13F. JSON7 of the 30 tracked managers held STRO at their latest 13F, $35.2M in total at quarter-end prices. Millennium Management is the largest at $12.2M (0.0% of its portfolio) as of 2026-06-30. Over the prior quarter 3 added shares and 3 cut.
| Fund | Quarter | Shares | Value | Of portfolio | Change in shares |
|---|---|---|---|---|---|
| Millennium Management | 2026-06-30 | 366K | $12.2M | 0.00% | +156K |
| Point72 Asset Management | 2026-06-30 | 238K | $7.9M | 0.01% | -454K |
| Two Sigma Investments | 2026-06-30 | 202K | $6.7M | 0.00% | +137K |
| Citadel Advisors | 2026-06-30 | 102K | $3.4M | 0.00% | -16K |
| Renaissance Technologies | 2026-06-30 | 86K | $2.9M | 0.00% | -12K |
| Fisher Asset Management | 2026-06-30 | 35K | $1.2M | 0.00% | 0 |
| D. E. Shaw & Co. | 2026-06-30 | 30K | $1.0M | 0.00% | new |
Only the 30 tracked managers on the funds hub; a 13F reports long positions in US listed stock at quarter end, 45 days late, and says nothing about shorts or positions sold since.
What this page is
Sutro Biopharma in the regulatory record
Regulators publish company data in separate files that never sit next to each other: FINRA's twice-monthly short interest, its daily short sale volume, the SEC's fails-to-deliver counts, and each insider's Form 4. A company page puts those series for one ticker on one URL, with planned sales, large holders, 13F holders and financials beside them, so the short position, the daily flow, the settlement fails and what insiders are doing can be read together.
Each section has its own history table, a one-line summary of the latest figures and its own JSON and CSV links, and says when its source last updated.
This page follows Sutro Biopharma (STRO), SEC CIK 1382101, listed on Nasdaq, classified by the SEC as biological products, (no diagnostic substances). The cross-market tables live on the short interest and insider transactions hubs.
Source and updates
- Short interest
- FINRA consolidated short interestSource: FINRA.Twice a month, about eight business days after settlement. Latest 2026-10-15.JSON and CSV
- Daily short volume
- FINRA Reg SHO daily filesSource: FINRA.Every trading day, the morning after FINRA posts it. Latest 2026-11-02.JSON and CSV
- Fails to deliver
- SEC fails-to-deliver dataSource: SEC.Twice a month, a few weeks after the half month ends. Latest 2026-09-30.JSON and CSV
- Planned sales
- SEC EDGAR Form 144Source: SEC.New notices appear shortly after the SEC posts them; a notice is filed on or before the sale. Latest 2026-01-20.JSON and CSV
- Large holders
- SEC EDGAR Schedule 13D and 13GSource: SEC.New filings appear shortly after the SEC posts them. A 13D is due within five business days of crossing 5%; a 13G follows the passive schedule. Latest 2026-08-14.JSON and CSV
- 13F holders
- SEC EDGAR Form 13F-HRSource: SEC.Quarterly, filed within 45 days of quarter end; 30 tracked managers. Latest 2026-06-30.JSON and CSV
- Earnings dates
- SEC EDGAR 8-K filings (Item 2.02)Source: SEC.Twice a day. Reported dates come from the company's 8-K filings; the next date is marked as an estimate until the 8-K arrives. Latest 2026-08-12.JSON and CSV
- Insider trades
- SEC EDGAR Form 4Source: SEC.New filings appear shortly after the SEC posts them; they're due two business days after the trade. Latest 2026-09-18.JSON and CSV
- Company record
- EDGAR filing index for CIK 1382101Ticker, name and exchange from the SEC's company list, refreshed weekly.
- Rate limits
- 10 requests a minute without a key, 30 with a free key from a free account.
How to read it
- Read the position against the flow: rising short interest with a high daily short share is new shorting; rising short interest with a normal short share is old shorts holding on.
- Insider buys next to a large short position are rare and stand out; insider sells next to one are common and mean little.
- Fails to deliver matter relative to the float, not in absolute shares; a million failed shares in a mega cap is noise.
Analysis of what the data shows, not advice. XOOMAR does not recommend buying, selling or holding anything.
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Datasets
Frequently Asked Questions
How much of STRO is sold short?
1,960,929 shares were held short at the 2026-10-15 settlement, 6.3 days of average volume. FINRA publishes the next count about eight business days after the 15th and the last business day of the month.
What is STRO's daily short volume?
On 2026-11-02, 22,104 of the 30,953 STRO shares reported to FINRA were sold short, 71.4% of the day's reported volume. Short volume is a flow for one day, not a position.
Does STRO have fails to deliver?
The SEC's latest file shows 8 STRO shares failed to deliver at settlement 2026-09-30. Fails are reported per settlement date and published twice a month with a lag.
Are STRO insiders buying or selling?
No open-market insider trades were reported for STRO in the last 90 days. The most recent filings are listed below. Latest filing: Gerber Hans-Peter (CHIEF SCIENTIFIC OFFICER) on 2026-09-18.
Have STRO insiders filed to sell?
1 Form 144 notice on file for STRO worth $131K at the prices reported; 0 in the last 90 days worth $0. Latest: BARBARA LEYMAN filed on 2026-01-20 to sell 8,929 shares ($131K) from 2026-01-20.
Who owns 5% or more of STRO?
15 holders report 5% or more of STRO in their latest filing, all on Schedule 13G (passive). The largest reported stake is Joseph Edelman at 7.9% of the class (1,304,846 shares), filed 2026-08-14 for an event on 2026-06-30.
Which tracked 13F managers own STRO?
7 of the 30 tracked 13F managers held STRO shares at their latest filing, $35.2M in all. The largest: Izzy Englander's Millennium Management (366K shares, $12.2M), Steve Cohen's Point72 Asset Management (238K shares, $7.9M), Two Sigma Investments (202K shares, $6.7M), Ken Griffin's Citadel Advisors (102K shares, $3.4M), Renaissance Technologies (86K shares, $2.9M), Ken Fisher's Fisher Asset Management (35K shares, $1.2M). The table above lists all 7.
Data on this page is provided for informational purposes only and is not financial advice. See our editorial policy.